在大肠杆菌中表达的重组Hepcidin融合蛋白以包涵体形式存在,其N端带有6个组氨酸。以Ni2+-IDA-Sepharose Fast Flow为层析介质,在变性条件下以不同的咪唑和pH值洗脱方式对Hepcidin融合蛋白的纯化效果进行了比较,确定了该融合蛋白的金属...在大肠杆菌中表达的重组Hepcidin融合蛋白以包涵体形式存在,其N端带有6个组氨酸。以Ni2+-IDA-Sepharose Fast Flow为层析介质,在变性条件下以不同的咪唑和pH值洗脱方式对Hepcidin融合蛋白的纯化效果进行了比较,确定了该融合蛋白的金属螯合层析纯化条件。以60 mmol/L咪唑洗脱杂蛋白,然后将pH值降至4.0洗脱融合蛋白,纯化后的融合蛋白纯度大于95%,而且不含咪唑,有利于下一步Hepcidin的制备。金属螯合层析中融合蛋白收率不低于90%。Ni2+-IDA-Sepharose Fast Flow对该融合蛋白的吸附量为30.4 mg/mL。展开更多
An immobilized metal ion affinity membrane was prepared by plasma-induced graft polymerization of glycidyl methacrylate (GMA) onto a porous polypropylene(PP), followed by chemical conversion of epoxide group of the GM...An immobilized metal ion affinity membrane was prepared by plasma-induced graft polymerization of glycidyl methacrylate (GMA) onto a porous polypropylene(PP), followed by chemical conversion of epoxide group of the GMA grafted membrane into an iminodiacetate(IDA) group, and chelation with copper ion. The effect of plasma discharge condition, GMA monomer concentration and grafting time on the degree of GMA grafting was studied and the optimum condition for plasma treatment of membrane was:10 W for 30 s, and that for grafting is 30 h at a concentration of 1 mol· L -1 GMA.Under this condition, a maximum grafting degree of 13.28% was obtained. The spectra of IR and XPS shows that GMA and IDA had been attached to the PP membrane after grafting and coupling. The nonselective adsorption of PP membrane had been significantly reduced after the H 2SO 4 treatment of the IDA coupled membrane. Finally, the isotherm adsorption of bovine serum albumin (BSA) on the immobilized metal ion affinity membrane was measured and the adsorption capacity of BSA increased with the degree of grafting. When BSA concentration was 1080 μg·ml -1 ,the adsorption ability of the affinity membrane with a grafting degree of 5.3% was nearly twice as much as that membrane with a grafting degree of 4.66%.展开更多
对利用金属离子亲和层析纯化重组类人胶原蛋白过程中使用的金属离子进行了比较,从而对分离纯化的条件进行优化。在相同实验条件下,用4种金属离子柱分离纯化目的蛋白。结果显示,经4种金属离子柱纯化后镍柱的总蛋白收获率最高,铜柱与锌柱...对利用金属离子亲和层析纯化重组类人胶原蛋白过程中使用的金属离子进行了比较,从而对分离纯化的条件进行优化。在相同实验条件下,用4种金属离子柱分离纯化目的蛋白。结果显示,经4种金属离子柱纯化后镍柱的总蛋白收获率最高,铜柱与锌柱居中,钙柱最低;而柱保留时间则为锌柱最高(12.38 m in),钙柱最低(8.25 m in);钙柱洗脱时所需咪唑解离初始浓度最低(100 mmol/L),锌柱最高(200 mmol/L);对SDS-PAGE电泳图进行分析得纯化后类人胶原蛋白的纯度分别为:镍柱82.8%,铜柱83.4%,锌柱96.2%,钙柱94.3%。由此可见锌柱对目标蛋白的亲和力最高,且纯化后类人胶原蛋白的纯度也最高。因此,确定锌离子作为亲和层析纯化重组类人胶原蛋白的金属离子。展开更多
Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their ...Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.展开更多
文摘在大肠杆菌中表达的重组Hepcidin融合蛋白以包涵体形式存在,其N端带有6个组氨酸。以Ni2+-IDA-Sepharose Fast Flow为层析介质,在变性条件下以不同的咪唑和pH值洗脱方式对Hepcidin融合蛋白的纯化效果进行了比较,确定了该融合蛋白的金属螯合层析纯化条件。以60 mmol/L咪唑洗脱杂蛋白,然后将pH值降至4.0洗脱融合蛋白,纯化后的融合蛋白纯度大于95%,而且不含咪唑,有利于下一步Hepcidin的制备。金属螯合层析中融合蛋白收率不低于90%。Ni2+-IDA-Sepharose Fast Flow对该融合蛋白的吸附量为30.4 mg/mL。
文摘An immobilized metal ion affinity membrane was prepared by plasma-induced graft polymerization of glycidyl methacrylate (GMA) onto a porous polypropylene(PP), followed by chemical conversion of epoxide group of the GMA grafted membrane into an iminodiacetate(IDA) group, and chelation with copper ion. The effect of plasma discharge condition, GMA monomer concentration and grafting time on the degree of GMA grafting was studied and the optimum condition for plasma treatment of membrane was:10 W for 30 s, and that for grafting is 30 h at a concentration of 1 mol· L -1 GMA.Under this condition, a maximum grafting degree of 13.28% was obtained. The spectra of IR and XPS shows that GMA and IDA had been attached to the PP membrane after grafting and coupling. The nonselective adsorption of PP membrane had been significantly reduced after the H 2SO 4 treatment of the IDA coupled membrane. Finally, the isotherm adsorption of bovine serum albumin (BSA) on the immobilized metal ion affinity membrane was measured and the adsorption capacity of BSA increased with the degree of grafting. When BSA concentration was 1080 μg·ml -1 ,the adsorption ability of the affinity membrane with a grafting degree of 5.3% was nearly twice as much as that membrane with a grafting degree of 4.66%.
文摘对利用金属离子亲和层析纯化重组类人胶原蛋白过程中使用的金属离子进行了比较,从而对分离纯化的条件进行优化。在相同实验条件下,用4种金属离子柱分离纯化目的蛋白。结果显示,经4种金属离子柱纯化后镍柱的总蛋白收获率最高,铜柱与锌柱居中,钙柱最低;而柱保留时间则为锌柱最高(12.38 m in),钙柱最低(8.25 m in);钙柱洗脱时所需咪唑解离初始浓度最低(100 mmol/L),锌柱最高(200 mmol/L);对SDS-PAGE电泳图进行分析得纯化后类人胶原蛋白的纯度分别为:镍柱82.8%,铜柱83.4%,锌柱96.2%,钙柱94.3%。由此可见锌柱对目标蛋白的亲和力最高,且纯化后类人胶原蛋白的纯度也最高。因此,确定锌离子作为亲和层析纯化重组类人胶原蛋白的金属离子。
基金supported by grants from the Brazilian Agency Coordination of Graduate Level Training(CAPES,project 0366/09-9)State of So Paulo Research Support Foundation(FAPESP-Brazil,project 2005/60159-7)
文摘Endotoxins(also known as lipopolysaccharides(LPS)) are undesirable by-products of recombinant proteins,purified from Escherichia coli.LPS can be considered stable under a wide range of temperature and pH,making their removal one of the most difficult tasks in downstream processes during protein purification.The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration.Immobilized metal affinity chromatography(IMAC) enables the affinity interactions between the metal ions(immobilized on the support through the chelating compound) and the target molecules,thus enabling high-efficiency separation of the target molecules from other components present in a mixture.Affinity chromatography is applied with Ca2+-iminodiacetic acid(IDA) to remove most of the LPS contaminants from the end product(more than90%).In this study,the adsorption of LPS on an IDA-Ca2+ was investigated.The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal.It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads.The factors such as pH(4.0 or 5.5) and ionic strength(1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than100 EU/mL and 100 000 EU/mL.This new protocol represents a substantial advantage in time,effort,and production costs.
